My logic: I chose theory and hypothesis here, as the first line does talk about a sort of theory of how bacteria will behave. But here, the ans. is A + C - can you please help me understand why my logic is wrong and what is the correct logic to use here?
Also, when and how do we decide that we should pick non-pair answer choices in SE?
You’ve stumbled upon the exceedingly rare situation where the correct answer is not a pair of direct synonyms.
The instructions for SE questions read as follows:
Identify the two choices that lead to a complete, coherent sentence while producing sentences that mean the same thing
Nowhere does it specify that the two words have to be synonyms.
In fact, the ETS website says this about solving SE questions:
Don’t simply look among the answer choices for two words that mean the same thing. This can be misleading for two reasons.
First, the answer choices may contain pairs of words that mean the same thing but do not fit coherently into the sentence.
Second, the correct pair of words may not mean exactly the same thing, since all that matters is that the resultant sentences mean the same thing [emphasis added].
To reiterate, though, this situation almost never happens. The vast majority of the time you will be pairing synonyms as usual.
In this particular case, theory/hypothesis do not work logically in the blank and should have been eliminated. While the sentence does describe a hypothesis that a bacterium succumbs to a virus to help the colony, the blank is not referring to that idea. Instead, the blank refers to the tendency that the bacterium has to succumb to the virus.
After you eliminate theory/hypothesis, you are left with
A: susceptibility describes a tendency via vulnerability C: characteristic describes a tendency via typicality
D: juxtaposition doesn’t describe a tendency
E: collision doesn’t describe a tendency